Bill,
You didn't mention the serial number of your coupe.
I find NO record of an "original eight gallon terneplate tank" ever being used in by ERCO on "production" airframes. All terneplate wing tanks I have been able to identify were of nine gallon capacity. Prewar Ercoupes had a single nine gallon tank in the right wing and the five gallon fuselage tank for a total fuel capacity of fourteen gallons, per factory brochures.
Postwar production airframes added another nine gallon tank in the left wing for a total fuel capacity of twenty-three gallons. The nine gallon stainless steel replacement tanks for Serials through 812 (with the main gear mounting on the forward side of the main spar) are in the Parts Manual as Part Numbers 415-48083L & R. There would be no purpose in fitting tanks to production aircraft that reduce range.
When the factory changed to aluminum tanks at Serial No. 2623 (see note at rear of Service Manual), the fuselage tank capacity was increased to six gallons and total fuel capacity increased to twenty-four gallons. The nine gallon current production tanks are Part Numbers 415-48147 (left) and 415-48187 (right).
Eight gallon aluminum wing tanks were produced for a short period which could be retrofitted for original terneplate tanks without cutting the fuselage. It is apparent that ESM-49 came out subsequent to production of serial no. 4729 on 5/13/47, with ESM-50 following. ESM-50 describes replacement of wing terneplate tanks with a replacement aluminum tank "recently approved" by the CAA. Identified as part numbers 415-48197L & R. The significant reduction in available fuel capacity was conspicuously omitted by ERCO in ESM-50. It would seem that the reason these tanks were produced was to avoid the necessity of cutting holes in the fuselage skin per ESM-39. They are no longer available from Univair.
We must look to Aircraft Specification No. 718 for more information on the 48197 aluminum tanks (p. 4, item No. 108), clearly the elusive "eight gallon aluminum wing tanks", holding 7.7 gal. (ea.). Total fuel capacity with these tanks and a five gallon fuselage tank was 20.4 gallons.
Regards,
William R. Bayne
.____|-(o)-|____.
(Copyright 2010)
-
On May 12, 2010, at 22:57, Bill Liggett wrote:
<x-tad-bigger>Here is an update to this thread that I initiated. My mechanic and I discovered that my left wing tank was the nine gallon aluminum one that was the most recent design and is repairable. The right wing tank was the original eight gallon ternplate tank which cannot be repaired once it leaks. Both tanks had been coated at some point with sloshing compound. My mechanic didn’t want to risk putting a second layer of sloshing compound over the original one. </x-tad-bigger>
<x-tad-bigger> </x-tad-bigger>
<x-tad-bigger>In the end I bought a used nine gallon aluminum tank from Vernon Gregory to replace the old ternplate one and shipped both tanks to John Wright Jr. to be unriveted, cleaned of all sloshing compound, and resealed and pressure tested. Having looked into alternatives (including asking a local radiator shop to put a bead of solder on the leaking seams – they refused to assume the liability), I would strongly recommend the solution my mechanic and I ultimately arrived at. I look forward to getting the cleaned and tested tanks back in the next week or two. I hope this helps those faced with a similar situation, and relieves those with the wisdom to know I was asking for trouble looking for a local fix. Bill</x-tad-bigger>
